Hi Sebastian, On 17 May 2017 at 18:02, Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> wrote: > On 2017-05-17 07:45:39 [-0700], Eric Nelson wrote: >> Hi Fawad, > Hi Fawad, > >> On 05/17/2017 06:40 AM, Fawad Lateef wrote: >> > > > I'm not sure about the unhandled page fault, but the stalls may be >> > > > because of the SDMA driver. >> > > > >> > > > See this patch in the Freescale/NXP community for kernel 4.1: >> > > > https://github.com/Freescale/meta-freescale/blob/master/recipes-kernel/linux/linux-fslc-imx-rt/0003-Work-around-CPU-stalls-in-the-imx-sdma-driver.patch > > That is something I see for the first time. The description says that it > leads to this stall but it fails to explain _how_ it got there. > >> > > Thanks for the patch link. I will give it a try. >> > >> > Talked to hardware manufacturer and they applied the patch. >> > >> > Still that SDMA is only used for NOR flash and only u-boot and its >> > environment are stored in nor flash. So not sure if that is going to >> > help in any case. >> > >> >> SDMA is used for much more than NOR flash (SSI, USB, and sometimes >> UARTs). >> >> > So I would really like few more suggestions OR confirmations about ARM >> > (cortex-A9 based imx6) (preemept)-RT support/patches are stable and >> > can be used for final products. >> > >> >> I don't have any experience with the RT patches on 4.9 or later >> kernels, but do know that they're being used on i.MX6 with the >> vendor kernels (3.10.x, 4.1.x). > > I just looked into a few boot logs and it seems the Phyflex board (imx6 > quad) bootet v4.9.27-rt18, run cyclictest including some tests and > nothing produced this "unhandled page fault" you mention here. This > includes the previous RT version in the v4.9 line. > Thanks, seems like RT patches are quite stable for ARM then. > Of this "page fault" happens on boot, it has to do something without > your .config + hw combination. If it happens at rune-time it is probably > triggered by a driver or an application is triggering this. > Yes, this happens at run-time and not always. Sometimes hardware just hangs/stalls. As now RT is widely used on ARM so to me seems like it something related to hardware design/setting OR application. Another question: Is RT user-space application can make kernel/system crash? As to me kernel should kill the app but let itself running _but_ not sure in the case of RT patched kernel. >> Regards, >> >> >> Eric > > Sebastian Thanks, Fawad Lateef _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
